The present invention is in the field of low molecular weight compounds which are the reaction products of epoxy and sulfonamide compounds and compositions, more particularly the present invention relates to the reaction product of at least one diepoxy compound and optionally at least one monoepoxy compound, and at least one sulfonamide compounds and related compositions useful as lacquers, coatings, and polymer concentrates.
U.S. Pat. No. 2,510,886 discloses the reaction product of sulfonamide, phenol and epoxy compounds useful in the manufacture of varnishes and coating compositions, molding compositions, adhesives, and films. The compounds are relatively high molecular weight, being made from polyhydric phenols and polyepoxides. The final reaction products are infusible.
U.S. Pat. No. 2,712,001 discloses compounds of sulfonamide and epoxide used in compositions which are useful to make molding compositions and articles, adhesives, films and fibers. The epoxides are characterized as complex epoxides made from polyhydric phenols an polyfunctional chlorohydrins containing both terminal epoxy groups and terminal primary hydroxyl groups. The complex epoxides reacted with the sulfonamides will have varying properties depending on the proportion of the reactants and degree of polymerization. The complex epoxides include the reaction product of bisphenol and epichlorohydrin. The reaction products, unless too highly polymerized are soluble in solvents such as acetone, methyl ethyl ketone, and diacetone alcohol and can be used to make clear or pigmented varnishes. The reaction products can further react to form an infusible state and an insoluble product. These compounds include a relatively high concentration of hydroxyl groups which is necessary to attain these results.
Sulfonamide based resins such as resins based on furfural and sulfonamide, and formaldehyde and sulfonamide are known from patents such as U.S. Pat. Nos. 1,840,596, 1,908,159 and 2,609,356. Pigmented sulfonamide formaldehyde-type resins are disclosed in U.S. Pat. No. 2,938,873.
Lacquers are coatings used to protect objects from corrosion, damage and for decorative purposes. A typical air dried lacquer consists of a polymeric binder, resinous modifiers, stabilizers, plasticizers, solvents, and optionally pigments and dyes. In air-dried lacquers the polymeric binders and the resinous modifiers are usually thermoplastic. The resinous modifiers are usually low molecular weight natural or synthetic resins having the ability to improve hardness, adhesion, water resistance, and overall coating durability. Known resin modifiers for lacquers include acrylic oligomers, rosin esters, hydrocarbon resins, ketone formaldehyde resins and toluene sulfonamide formaldehyde resins. Toluene sulfonamide formaldehyde resins are especially useful in lacquers based on organic cellulose derivatives and vinyl polymers.
Toluene sulfonamide formaldehyde resins are light in color and have excellent compatibility with a variety of polymers. They release solvent fast and promote adhesion to a variety of surfaces. Their properties can be varied by changing the ratio of formaldehyde to sulfonamide. The melting point of these resins is usually between 60.degree. C. and 80.degree. C. The main disadvantage of toluene sulfonamide formaldehyde resin is their tendency to release free formaldehyde which is a toxic substance.